Sustainability

Sustainability is defined as the capability of being sustained, supported, and able to keep existing (indefinitely).

Self Sustainability is one goal of Oxygen not Included, as the game does not have an ending. Getting all achievements might be a goal to some players, but is nowhere defined to be the end goal. Optimal systems are needed, using the resources in the closed environment refined into something useful to provide longer life support for the colony and its Duplicants, preferably with no byproducts and the lowest Power requirements. Renewable resources are also an important source of materials for a sustainable colony.

This flowchart shows possible resource flows in a sustainable base. Power can sustainably be produced using Solar Panels. Some (unnecessary) Resources are excluded for the sake of clarity.

Duplicants require only two things to survive indefinitely in their colony: Oxygen and Food:
 * Oxygen is produced via om Water, Algae, Polluted Oxygen, Rust and Salt. It can also be obtained via various Geysers, as Polluted Oxygen.
 * Algae can be found naturally or produced from Slime.
 * Water is produced by Geysers and as a by-product from machines
 * Food must be produced by Duplicants, as Muckroot and Hexalent Fruit are finite resources.
 * Plants can be farmed to obtain ingredients for Food. They can be farmed either in Wild Growth, requiring no fertilizer and irrigation, or domestically, requiring additional resources, but growing four times faster. The availability of renewable resources needs to be considered to decide which method is better suited for a colony.
 * Critters can be ranched to obtain Meat for high quality Foods and also Raw Egg, when excess eggs are cracked, which can be cooked into Omelette. However, Critters may need to be fed and groomed to provide the necessary food.

Oxygen and Food production can also be integrated into industrial production chains, using by-products that would have been disposed of otherwise. For example: Oxygen is produced by an Electrolyzer using Water, Water is produced from the Steam produced by a Polymer Press using Petroleum, and Petroleum is produced from an Oil Refinery using Crude Oil.

Below is a summary of required resources for Oxygen production. Items italicized are expanded earlier in the list; bold items indicate a geyser.

Oxygen
Notes:
 * Algae
 * Slime
 * Polluted Oxygen
 * Water
 * Petroleum
 * Crude Oil
 * Slime
 * Polluted Water
 * Natural Gas
 * Polluted Water
 * Crude Oil
 * Petroleum
 * Slime
 * Polluted Oxygen
 * Polluted Water
 * Polluted Dirt
 * Rot Pile
 * Slime